The long-term goal of our research agenda is to identify the mechanisms associated with rotator cuff tendinopathy (impingement syndrome) and subsequently evaluate novel treatment strategies that address these mechanisms. The objectives of this application are to study the muscle patterns in patients with rotator cuff tendinopathy as well as the effects of both pain and exercise on these patterns. Our first hypothesis is that pain relief from a shoulder injection will result in increased rotator cuff actiity. Our second hypothesis is that patients with tendinopathy will demonstrate improved rotator cuff muscle activity following a six-week exercise program and that this improvement will be higher in patients that respond favorably to treatment. Our final hypothesis is that patients with cuff tendinopathy will show decreased rotator cuff activity compared to healthy subjects. We plan on addressing these hypotheses using several novel techniques for muscle activity assessment.